hello, I made a modification to ssl-proxy-openssl.c (patch attached) zo that it a) disconnects when no client certificate is presented b) checks the client certificate against the crl for our root cert. (so you can't use a revoked client cert.) c) returns the CommonName from the client cert. in ssl_proxy_get_peer_name (this way it's easier to use dovecot as imap-proxy with a passwd-like userdb, ssl_require_client_cert and ssl_username_from_cert, it "binds" the emailuser to the clientcertificate, a clientcert. can access only the account from the userdb) in order to use it, the CAfile must be a file which contains the CAcertificate (pem format) followed by the CRL (also in pem format). (servercert and the clientcerts are signed with a self-signed rootcert) there are some issues with the patch: a) it needs openssl > 0.9.7 for the CRL checking b) ssl_verify_client_cert now returns 0 in case of an invalid cert. was there a reason why it always returned 1? c) i'm not too happy with the commonname extraction code, is it secure?? d) i've no experience with programming openssl or dovecot e) i haven't programmed in C for at least 8 years...... does anyone here have more issues, corrections, comments on the patch? can/should this functionality be implemented in dovecot? (conf-file option?) -- groeten, HenkJan Wolthuis --- ssl-proxy-openssl.c.orig 2006-04-04 10:32:58.000000000 +0200 +++ ssl-proxy-openssl.c 2006-05-11 14:08:02.000000000 +0200 @@ -11,6 +11,7 @@ #include #include #include +#include #ifdef HAVE_OPENSSL @@ -508,9 +509,42 @@ if (x509 == NULL) return NULL; /* we should have had it.. */ + + // ORIG: X509_NAME_oneline(X509_get_subject_name(x509), buf, sizeof(buf)); + // ORIG: name = t_strndup(buf, sizeof(buf)); + // ORIG: X509_free(x509); + + /* HJHJ get CommonName from peer-certificate */ X509_NAME_oneline(X509_get_subject_name(x509), buf, sizeof(buf)); - name = t_strndup(buf, sizeof(buf)); + + char *tmp; + char *start; + start = buf; + tmp = strstr( buf, "CN=" ); + if( NULL != tmp ) + { + if( strlen(tmp) > 3 ) /* CN= + something */ + { + start = tmp + 3; + tmp = strstr( start, "/" ); + if( NULL != tmp ) /* tmp == NULL: CN is last element in buf */ + { *tmp = '\0'; } + } + else /* empty CN= */ + { + *start = '\0'; + i_warning("get_peer_name empty CN="); + } + } + else + { + *start = '\0'; + i_warning("get_peer_name NO CN="); + } /* CN= not found (no certificate or certificate without commonname??) */ + + name = t_strndup(start, strlen(start) ); X509_free(x509); + /* HJHJ */ return *name == '\0' ? NULL : name; } @@ -582,10 +616,26 @@ proxy = SSL_get_ex_data(ssl, extdata_index); proxy->cert_received = TRUE; + // ORIG: if (!preverify_ok) + // ORIG: proxy->cert_broken = TRUE; + + // ORIG: return 1; + + /* HJHJ */ + char buf[1024]; + X509_NAME_oneline( X509_get_subject_name(ctx->current_cert),buf,sizeof(buf)); + if (!preverify_ok) + { proxy->cert_broken = TRUE; + i_warning("BAD CERT %s: %s",X509_verify_cert_error_string(ctx->error),buf); + } + else + { i_warning("CERT: %s",buf); } - return 1; + return preverify_ok; + /* HJHJ */ + } static int @@ -666,10 +716,20 @@ if (getenv("SSL_VERIFY_CLIENT_CERT") != NULL) { SSL_CTX_set_verify(ssl_ctx, SSL_VERIFY_PEER | - SSL_VERIFY_CLIENT_ONCE, + SSL_VERIFY_FAIL_IF_NO_PEER_CERT, ssl_verify_client_cert); } + /* HJHJ */ +#if OPENSSL_VERSION_NUMBER >= 0x00907000L + X509_STORE *store; + if( (store=SSL_CTX_get_cert_store(ssl_ctx)) != NULL ) + { X509_STORE_set_flags( store, X509_V_FLAG_CRL_CHECK | X509_V_FLAG_CRL_CHECK_ALL); } + else + { i_warning("X509 get cert store failed..."); } +#endif + /* HJHJ */ + /* PRNG initialization might want to use /dev/urandom, make sure it does it before chrooting. We might not have enough entropy at the first try, so this function may fail. It's still been